Phaeosphaeria thysanolaenicola Phookamsak & K.D. Hyde, sp. nov., Index Fungorum number: IF550735.
Etymology: Referring to the host on which the fungus was found.
Holotypus: MFLU 11-0157
Pathogen associated with Paraphaeosphaeria on leaves of Thysanolaena maxima. Sexual state: Ascomata 70–100 µm high, 100–130 µm diam., scattered or sometimes clustered, immersed, visible as raised, black dots on the host surface, uni- to bi-loculate, subglobose, brown to dark brown, ostiole central, with minute papilla. Peridium 5–10 µm wide, thin-walled, of equal thickness, composed of 1–3 layers of brown to dark brown, pseudoparenchymatous cells, arranged in textura angularis. Hamathecium composed of numerous, 2–5 µm wide, filiform, broad cellular pseudoparaphyses, with distinct septa, slightly constricted at the septa, embedded in a gelatinous matrix, rarely anastomosing at the apex. Asci (41.5–)43–50(–57) × 7–9 µm ( = 49.3 × 8.4 μm, n = 25), 8-spored, bitunicate, fissitunicate, broadly cylindrical or cylindric-clavate, sessile to subsessile, apically rounded with ocular chamber. Ascospores (15–)17–19(–20) × 3–4 µm ( = 17.8 × 3.8 μm, n = 30), overlapping 1–3-seriate, phragmosporous, narrowly fusiform, with obtuse ends, yellowish-brown to brown, 3-septate, rarely 1–2-septate, slightly constrict at the central septum, straight to curved, rough-walled, echinulate, surrounded by mucilaginous sheath. Asexual state: Unknown.
Culture characters: Colonies on PDA 33–35 mm diam. after 4 weeks at 25–30 ◦C, white to pale yellowish-brown at the edge, white with grey sectors in the centre; reverse white to yellowish at the edges, becoming orange brown to grey at the centre with orange radiations separating the edges from the centre; medium dense, circular to irregular, flattened to raised, or umbonate, rough with entire to slightly undulate edge, floccose to velvety or cottony, radiating in the lower part, not producing pigments.
Material examined: THAILAND, Chiang Rai Province, Phan District, Pukang Waterfall, on living leaves of Thysanolaena maxima Kuntze (Poaceae), 22 May 2010, R. Phookamsak (RP0036) (MFLU 11-0157, holotype), ex-type living culture = MFLUCC 10-0563 = MUCL.
Notes: Phaeosphaeria thysanolaenicola is most similar to Ph. oryzae as they share a similar ascoma, asci and ascospore size range. However, they differ in habitat and host preferences, as Ph. thysanolaenicola is associated with other fungi on leaf spots of Thysanolaena maxima. Whereas Ph. oryzae was found as a saprobe on Oryzae sativa. The ITS pair wise comparison shows that they differ in eight base positions. Phylogenetic analysis performed with a combination of ITS, LSU, RPB2 and TEF1 genes shows that Ph. thysanolaenicola forms a clade with Ph. chiangraina. Phaeosphaeria thysanolaenicola differs from Ph. chiangraina in its smaller asci and ascospores, habitat, host occurrence and ascospore ornamentation. Phaeosphaeria thysanolaenicola has echinulate ascospores while Ph. chiangraina has smooth-walled ascospores.
Fig. 1 Phaeosphaeria thysanolaenicola (MFLU 11-0157, holotype). a Ascomata on host surface. b Section through ascoma. c Section through peridium. d Cellular pseudoparaphyses. e–h Asci. i–l Ascospores. Scale bars: b = 20 µm, c, e, f, g, h, = 10 µm, d, i, j, k, l = 5 µm.
